For Redhat/CentOS/Fedora/SL distribution
Type the redhat-config-date command at the command line to start the time and date properties tool, run:
OR type setup and select time zone configuration. This tool is recommended for remote ssh text based sessions.
Select timezone configuration. Just follow on screen instructions to change the timezone.
If you are using Debian / Ubuntu Linux
To change the timezone for you run the following command as root user:
# dpkg-reconfigure tzdata
Again, just follow on screen instructions.